This invention relates to vertical fencing, and in particular to vertical tube fencing.
Vertical fencing has been known for a number of years. This fencing comprises (in use) a plurality of vertical fence members which are supported by two substantially horizontal rails, a rail being located adjacent the top and bottom of the fence members. The fencing is adapted as security fencing to prevent access by unauthorised persons, and so the fence members are sufficiently closely spaced to prevent such access. Typically the fence members are of a length to prevent or reduce the likelihood that the fence can be climbed, and the rails are positioned sufficiently far apart to impair their use as a climbing aid for a person wishing to climb over the fence. In addition, the fence members project beyond the top rail, and their free ends can carry spikes or other features (which may be partly decorative), which spikes or features act to dissuade a person from climbing over the fence.
Vertical fencing is typically manufactured in sections, each section comprising a number of fence members and two rails. The sections are manufactured off-site and are then transported to the fence site. The rails are adapted to be connected to posts which are erected on the fence site at spaced positions along the line of the fence, two adjacent posts supporting either end of the rails of each section.
If the fence is at a site at which the ground is flat and horizontal the fence members can be permanently secured to the rails (as by welding), and can be exactly perpendicular to the rails, so that in the assembled fence the rails are horizontal and the fence members are vertical. However, it is often the case that the ground at the fence site is not flat and/or horizontal, so that if permanently secured fence members are used it is necessary to xe2x80x9cstepxe2x80x9d the fence, i.e. to have one section higher or lower than an adjacent section to follow the slope of the ground. Such stepping is often visually unacceptable to the fence builder or architect. In addition, such stepping produces difficulties in fitment of the sections to the posts; thus, often the fitting means for the rails are pre-secured to the post(s), and it is difficult or impossible accurately to pre-secure the fitting means if the positions of these vary according to the slope of the ground adjacent the erected post location.
To overcome these difficulties, it is desired that the fence follow the contours of the ground, i.e. whilst the fence members remain vertical the rails can be pivotted relative thereto so that the rails are no longer perpendicular to the fence members but can be substantially parallel to the (non-horizontal) ground. A fence section in which the fence members can pivot relative to the rails is referred to as xe2x80x9cself-adjustingxe2x80x9d. Typically, up to 20xc2x0 of pivotting movement can be accommodated by self-adjusting vertical fencing.
Self-adjusting vertical fencing systems have been known for many years. One such system is known in the trade as xe2x80x9cNibalxe2x80x9d, and in this system the fence members are fitted to the rails by way of apertures in the rails; the fence members are then crimped (or xe2x80x9cribbedxe2x80x9d) adjacent the apertures so that subsequent removal from the rail is prevented. However, the crimping allows sufficient flexibilty in the joint between the fence members and the rails so that self-adjustment is possible. The xe2x80x9cNibalxe2x80x9d system is shown in the 1930 catalogue of Baylis, Jones and Baylis, a well-known U.K. fencing manufacturer.
As described, the xe2x80x9cNibalxe2x80x9d system relies upon the fence members being crimped. Traditionally, the fence members were of substantially circular cross-section solid steel bar 16 mm in diameter (or thereabouts). The substantial bar thickness was required to prevent adjacent bars being bent and separated, which could permit access through the fence. A fencing section would comprise two rails and perhaps twenty bars, and clearly such fencing sections were extremely heavy and so difficult and expensive to transport from the manufacturing location to the fence site.
Nowadays, it has become customary to use tubes as the fencing members rather than solid bars, the tubes being of a diameter and wall thickness sufficient to prevent or reduce the likelihood of bending and yet offering a substantial decrease in weight over an equivalent strength bar. Thus, xe2x80x9cvertical bar fencingxe2x80x9d has been largely replaced by xe2x80x9cvertical tube fencingxe2x80x9d.
However, it has not been found possible reliably to crimp the tubes used for vertical tube fencing, so that the xe2x80x9cNibalxe2x80x9d system is not practical for self-adjusting vertical tube fencing.
Notwithstanding that the xe2x80x9cNibalxe2x80x9d system is not practical for vertical tube fencing, architects, customers, and the like are still demanding self-adjustment, so that there is a requirement for an alternative to the xe2x80x9cNibalxe2x80x9d system which is suitable for vertical tube fencing.
The present invention therefore seeks to provide vertical tube fencing which is self-adjusting.
According to the invention, there is provided vertical fencing comprising a pair of rails and a plurality of fence members attached thereto, the fence members being pivotable relative to the rails, characterised in that the fence members are tubular, and in that each fence member carries a resiliently-biassed projection which is engageable with recess means in one of the rails.
Preferably, when the projection is engaged in the recess means movement of the fence member parallel to its longitudinal axis is limited. Accordingly, unauthorised removal of the fence member from the rail or rails is prevented.
Preferably also, when the projection is engaged in the recess means rotational movement of the fence member about its longitudinal axis is limited. Accordingly, if the fence members have asymmetric features fitted thereto (as for example may be provided by decorative end fittings), those features will be maintained in alignment along the fence.
Desirably, the projection should be a sufficiently tight fit within the recess so that longitudinal movement and rotation is substantially prevented, so that the possibility of rattling of the fence member relative to the rails is prevented or reduced.
Desirably, at least one of the rails comprises a channel section, the recess being provided by a notch or hole in an inturned part of the section. Accordingly, the recess can be substantially invisible when the fence section has been assembled, so that subsequent unauthorised removal of the projection from the recess is substantially or totally prevented.
Preferably, the resiliently-biassed projection is provided by a spring clip; preferably also the body of the clip is located within the fence member.
Desirably, only one of the rails has a recess for engagement by a projection. In such an embodiment, the other rail can be attached to the fence member by a pair of fixed pegs or the like. It will be understood that the retention and anti-rotation aspects of the projection and recess need only be provided on one of the rails, since removal of the fence member from, or rotation of the fence member relative to, the other rail is limited by said one of the rails.
Desirably, the fence member has a pair of resiliently-biassed projections, usefully projecting in opposed directions for engagement in opposed recesses.
Usefully, in the assembled condition the projection is substantially perpendicular to the plane of the fence section, so that the projection and recess can additionally provide the pivot point between the rail and fence member.